i=1;
r0=dis_sg(i,1);
r1=dis_sg(i,2);
r2=dis_sg(i,3);
r3=dis_sg(i,4);
point=zeros(4,3);
point(4,:)=threeball(x0,y0,z0,r0,x1,y1,z1,r1,x2,y2,z2,r2);
if isreal(point3)
    distan(4)=sqrt((point(4,1)-x3)^2+(point(4,2)-y3)^2+(point(4,3)-z3)^2);
else
    distan(4)=0;
end
point(3,:)=threeball(x0,y0,z0,r0,x1,y1,z1,r1,x3,y3,z3,r3);
point(2,:)=threeball(x0,y0,z0,r0,x2,y2,z2,r2,x3,y3,z3,r3);
point(1,:)=threeball(x1,y1,z1,r1,x2,y2,z2,r2,x3,y3,z3,r3);